feat(meshlet): add cluster LOD hierarchy & API upgrades

Implemented meshlet cluster LOD hierarchy with binary-to-4-ary conversion. Updated MeshletHierarchyNode to 4-ary structure. Enhanced SIMD optimizations in GGX mipmap generation. ResourceManager mesh/material creation now supports dynamic buffers and optional naming. Upgraded SPMD package to 1.3.2. Performed minor code cleanups and doc improvements.

src/Runtime/Ghost.Graphics.D3D12/D3D12ResourceDatabase.cs

@@ -317,7 +317,7 @@ internal unsafe class D3D12ResourceDatabase : IResourceDatabase
         _resources.Remove(handle.ID, handle.Generation);
 
 #if DEBUG || GHOST_EDITOR
-        _resourceName.Remove(handle, out var name);
+        _resourceName.Remove(handle, out _);
 #endif
     }